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Date: Tue, 9 Aug 2005 07:55:24 -0700 (PDT)
From: "James R. Phillips" <antiskid56-cygwin AT yahoo DOT com>
Reply-To: antiskid56-cygwin AT yahoo DOT com
Subject: Re: lapack packaging question
To: cygwin AT cygwin DOT com
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Eric,

To recap the discussion, the lapack package is designed so that a user can
download the source, and build a locally-optimized atlas blas library from
source, then install it by copying the resulting dll's to /usr/local/bin.  If
this optimization is not performed, a generic non-optimized blas library is
installed.  Information on how to do this is in the CYGWIN-PATCHES subdirectory
of the source tree.

Locating the non-optimized generic dll's in /usr/lib/lapack allows them to be
simply overridden by the optimized ones, by virtue of /usr/local/bin preceding
/usr/lib/lapack in the path.

This is not as convenient as Debian's packaging system for atlas, but it
definitely _is_ more in the spirit of the way atlas is designed to work - it is
designed to produce a locally optimized blas library by a repeated sequence of
compile, test, adjust parameters, until it converges on an optimal set of
compile-time parameters for the fastest operation of the blas.

At the request of the gsl maintainer, cblas interface functions and headers
were added to the library following release 3.0-1, so the release is now at
3.0-3.  Actually there are some minor flaws with the cygwin README file on
release 3.0-3, so I have a new one prepared to address that whenever it seems
important.

I am very interested to obtain user feedback from the preparation/use of the
optimized atlas blas libraries, so if you try compiling atlas, please let me
know how it works out for you.  Any other user feedback is welcome as well.

Thanks,

Jim Phillips


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